Cataract surgery can lower the risk of dementia by 30%, according to a study at Kaiser Permanente Washington. The Adult Changes in Thought (ACT) study is a long-standing, Seattle-based observational study of more than 5,000 participants over 65 years.
Researchers analysing longitudinal data of over 3,000 ACT study participants, found subjects who underwent cataract surgery had almost 30% lower risk of developing dementia from any cause, compared with those who did not, for at least a decade after surgery. Cataract surgery was also associated with lower risk of Alzheimer disease, dementia specifically.
Lead researcher Dr Cecilia S Lee, Associate Professor and Klorfine Family Endowed Chair in ophthalmology at the University of Washington School of Medicine, said the observational study adjusted for a number of potential confounders, yet still yielded a strong association. “This kind of evidence is as good as it gets in epidemiology,” said Dr Lee.
“This is really exciting because no other medical intervention has shown such a strong association with lessening dementia risk in older individuals.”
While the study did not look at mechanisms by which cataract surgery lessened dementia risk, the researchers hypothesise that people may be getting higher quality sensory input after cataract surgery, which might have a beneficial effect in reducing the risk of dementia.
Dr Lee said another hypothesis is that after cataract surgery, people are getting more blue light.
“Cataracts specifically block blue light, and cataract surgery could reactivate those cells,” she said.
The study was published in JAMA Internal Medicine.
Reference
Cecilia S. Lee, Laura E. Gibbons, Aaron Y. Lee, Ryan T. Yanagihara, Marian S. Blazes, Michael L. Lee, Susan M. McCurry, James D. Bowen, Wayne C. McCormick, Paul K. Crane, Eric B. Larson. Association Between Cataract Extraction and Development of Dementia. JAMA Internal Medicine, 2021; DOI: 10.1001/jamainternmed.2021.6990
